Unexpected Role of the Interlayer “Dead Zn2+” in Strengthening the Nanostructures of VS2 Cathodes for High‐Performance Aqueous Zn‐Ion Storage

Abstract Layered VS 2 holds great potential as a cathode material for aqueous Zn‐ion batteries owing to its large interlayer spacing, high electrical conductivity, and the rich redox chemistry of vanadium. Nevertheless, structural instability during charge/discharge severely hinders the further development of VS 2 cathodes. Herein, distinctive hierarchitectures of 1T‐VS 2 nanospheres assembled by nanosheets, which feature abundant active sites, superior electron/ion transport property, and robust structure, are developed. More intriguingly, Zn 2+ “pillars” residing in VS 2 interlayers, achieved by controlling the charge cut‐off voltage are first proven to reinforce the layered structure of VS 2 upon repeated Zn 2+ insertion/extraction, redefining the commonly perceived “dead Zn 2+ ”. Hence, exceptional rate performance (212.9 and 102.1 mA h g −1 at 0.1 and 5 A g −1 , respectively) and ultralong cycling life (86.7% capacity retention over 2000 cycles at 2 A g −1 ) are obtained. The rapid and highly reversible Zn‐ion (de) intercalation behavior within the VS 2 nanospheres is verified by first‐principles computations and multiple ex‐situ characterizations. Finally, the flexible quasi‐solid‐state rechargeable Zn battery employing the tailored VS 2 cathode demonstrates great application prospects in wearable devices. This work provides new perspectives for prolonging the lifespan of layered Zn‐storage materials by simply modulating the charge/discharge processes.